US4412892A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pretreatment of superalloys and stainless steels for electroplating
Assignee: United States Department of the Army
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Filing: 1981-07-13
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Granted: 1983-11-01
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Expires: 2001-07-13
Abstract
Abstract Process for activating surfaces of superalloys and stainless steels prior to electroplating a metal such as chromium thereon, whereby a metal deposit having excellent adhesion to the substrate is obtained. The article is activated by anodic etching in a novel activation solution containing about 55% to 80% by volume of H2SO4 and about 1% to 10% by volume of commercial 52% hydrofluoric acid, preferably an aqueous bath containing 65% by volume of 95-98% H2SO4 and 5% by volume of 52% hydrofluoric acid at 30 A/dm2 and 20 DEG C. for one minute.
Inventors
- 👤 Edward S. Chen
- 👤 William Baldauf
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 17:59
CPC Classifications
C; C25; C25D; C25D5/00; C25D5/34; C25F; C25F3/00; C25F3/02
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
80 words
A process for electroplating a metal on a substrate of superalloy, which comprises activating the substrate surface by anodic etching in an aqueous solution consisting essentially of about from 55% to 80% by volume of 95-98% sulfuric acid and about from 1 to 10% by volume of 52% hydrofluoric acid at a current density of at least 20 A/dm 2 , and electroplating the activated surface with a metal of the group consisting of chromium, nickel, cobalt, copper and iron.
Claim 2
Dependent Claim
80 words
A process for electroplating a metal on a substrate of superalloy, which comprises activating the substrate surface by anodic etching in an aqueous solution consisting essentially of about from 55% to 80% by volume of 95-98% sulfuric acid and about from 1 to 10% by volume of 52% hydrofluoric acid at a current density of at least 20 A/dm 2 , and electroplating the activated surface with a metal of the group consisting of chromium, nickel, cobalt, copper and iron.
Claim 3
Dependent Claim
13 words
A process according to claim 1 wherein the metal for electroplating is chromium.
Claim 4
Dependent Claim
21 words
A process according to claim 4, wherein the chromium is electroplated from an aqueous solution of chromic acid and sulfuric acid.
Claim 5
Dependent Claim
32 words
A process according to claim 1, wherein the activating solution consists essentially of an aqueous mixture of about 65% by volume sulfuric acid and about 3% to 7% by volume hydrofluoric acid.
Claim 6
Dependent Claim
25 words
A process according to claim 1, wherein the anodic etching is carried out at a current density of about 30 to 120 A/dm 2 .
Claim 7
Dependent Claim
21 words
A process according to claim 1, wherein the duration of the anodic activation treatment ranges about from 30 to 120 seconds.
Claim 8
Dependent Claim
23 words
The process according to claim 1, wherein the activated substrate surface is directly electroplated with the metal without an intermediate rinse with water.
Claim 9
Dependent Claim
20 words
The process according to claim 1, wherein the superalloy is selected from the group consisting of CG-27, U-700 and HS-25.
References Cited (Backward Citations)
US2044742A
Cited
US3287237A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-10-31 | 1987-05-02 | 1987-11-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-10-31 | 1991-05-02 | 1991-11-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-10-31 | 1995-05-02 | 1995-11-01 | $7700.00 | Window Closed / Lapsed |